The present disclosure relates to a backlight unit, and more particularly, to a backlight unit capable of improving optical efficiency, and a display device having the same.
Recently, various display devices are being developed to meet user's information requirements. Display devices include, for example, liquid crystal display devices, plasma display devices, organic electro-luminescent display devices and field emission display devices.
Among such display devices, liquid crystal display (LCD) devices, which display an image using liquid crystals, are being widely used throughout industry thanks to their several advantages such as slimness, lightness, low power consumption and low driving voltage.
The LCD device includes two substrates and liquid crystals interposed therebetween. A voltage applied across the two substrates controls orientation of the liquid crystals so that the LCD device displays an image.
The LCD device needs a backlight unit for irradiating light from the outside because the LCD device is a passive device that cannot emit light by itself.
However, a light source must be continuously operated because a related art backlight unit has to generate light in order for the LCD device to display an image, thus leading to an increase in power consumption.
Moreover, it is difficult for the related art backlight unit to provide brightness level beyond predetermined value due to a technical limitation and an increase in power consumption.
In order to improve optical efficiency, therefore, studies are being actively conducted on technologies for substituting a light source of a backlight unit lately.